We’re all human resources executives now. Or perhaps it’s just felt that way this week as the argument over whether José Mourinho was right to criticise Luke Shaw in public ran on longer than your average employment tribunal.

The young defender was singled out following Manchester United’s insipid 3-1 defeat to Watford last weekend. He was not the first individual to be treated in such a way by his manager this season: Eric Bailly, Daley Blind and Jesse Lingard have already felt the edge of Mourinho’s tongue. But the Portuguese was certainly unsparing. “Our left-back is 25 metres away instead of five,” he said of Shaw’s involvement in Watford’s crucial second goal. “Give him 25 metres and you have to press. But no, we wait. It is a tactical but also mental attitude.”

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There have been theories and counter theories as to why Mourinho did what he did. Murmurings from Shaw’s camp have suggested that the player has been left upset. United themselves have let it be known they see outspoken remarks as not only part of Mourinho’s character but in the tradition of Sir Alex Ferguson himself. None of these have resolved the key question though: whether such tactics are ever really effective.

The one big qualifier to this entire debate is that every individual is different and a relationship between a manager and an employee will differ from person to person. “Some players might respond to it you never know‚“ says David Pleat, the former Tottenham manager and director of football. “You don’t know what the relationship is between the player and manager. Neither do you know the motivation behind what was said and what they discussed in private. But to do it in public is normally a last resort. You can’t give a final warning to a player. You can to a member of staff, but not a player. So some managers might see this as an equivalent.”

Dr Steve Peters has worked as a sports psychiatrist for both Liverpool and Roy Hodgson’s England and says that aspects of behaviour will always remain opaque to a degree. “You would have to be a mind reader to know why someone would publicly criticise [an employee]. You would have to question them directly to find out their motives,” he says, adding “but sometimes people just don’t know why they have done something.”

Caveats to one side, it is clear that the downsides to public criticism are many and sizeable. The idea, for example, that some players will thrive under the pressure is unlikely to be true, says Peters. “Clearly very few people would react well to public criticism,” he says. “We are all unique individuals and react very differently depending on a number of factors. For example, we generally don’t get affected if we are robust or if what is happening is not of any importance to us. So it may not be about personality but about beliefs or abilities to manage emotions. But even if a criticism is justified it is possible that there will be a feeling of humiliation and a reaction to this to defend [yourself] or attack the comment. We are by nature emotional creatures and, for most, compassion is more powerful than a rebuke.”

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For Pleat, there are scenarios in which public criticism can have a positive effect, though not necessarily on the individual involved. “You might criticise your best player to show the younger members of your squad that you’re not afraid to challenge the top man. It can be motivational for them to see that,” he says. “But what you would never do is criticise a young player in public. It’s hard enough for them to break through the tough atmosphere of a dressing room as it is, without you knocking their confidence. It’s likely to alienate the rest of the squad who will look at what has happened and see it as unfair.”

And therein lies the rub. Because while a manager speaking out of turn in your place of work might lead to some awkward meetings, in top-flight football it could mean writing off millions of pounds. “Modern players are delicate commodities but they’re also very valuable,” says Pleat. “Even if they’re on what I’d call a minimal Premier League contract of £20,000 a week, that’s a million pounds a year that you’re putting at risk. A chairman might look at [a player who’s been criticised] and say: ‘I’ve now got a million pound liability.’”

In the febrile world of modern football there are few managers who could afford to take on a risk like that (though Mourinho might be an exception). In fact, much of what has changed in the game over the past two decades has helped swing the balance of power away from the manager to players and their agents. Players, after all, have social media on which to air their grievances, or the receptive ear of a friendly journalist. There is also the active antenna of the PFA, who could bring their well-resourced heft to bear on a dispute. As brutal as it might be, the public dressing down is one of the few tools that a manager has left in their arsenal. So if things stay sticky at Old Trafford, and maybe even if they do not, expect Mourinho to use it again.